In vehicle bodies such as the van type having a substantially vertical rear access opening, there is typically provided either a sideways type swinging tailgate that swings about a generally vertical axis and as a result requires little effort to open and close or a lift type tailgate that swings upward about a horizontal axis to open and as a result requires significant lifting effort to effect opening. For the convenience of the people using a vehicle having a lift type tailgate, it is desired that a power lift system be provided to relieve a person of the required lifting effort and particularly where the tailgate is a heavy singular gate or door that closes the entire rear access opening. However, there is limited space in the vehicle body for a power lift system with the capacity to handle the heavy lifting effort required of such a tailgate. Moreover, it is desirable that the tailgate be capable of being opened and closed manually independent of special conditioning of the power lift system and with minimum effort both as a matter of convenience and in the event the operation of the power lift system is not available for some reason such as a malfunction in the power lift mechanism or loss of power thereto.
Various forms of power lift tailgate systems have been proposed but they are typically complicated in structure and require considerable accommodating space in the vehicle body particularly where they use some form of spring system to assist in the operation of the tailgate such as by counterbalancing the weight of the tailgate. Furthermore, they typically require a control system and attendant components to switch between a power mode and a manual mode that will allow manual opening and closing free of the power lift mechanism.